Electrical apparatus



April 5, 1932.

P. H. DOWLING ELECTRICAL APPARAT US Filed April l, 1931 Posz'zz'0a fompemiure m5 II TOL0ad Fzlg. 5.

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INVENTOR. P, Du nflfn7,

ATTORNEY.

Patented Apr. 5, 1932 UNITED STATES PATENT OFFICE PHILIP H. DOWLING, CF SWISS'VALE, PENNSYLVANIA, ASSIGNOR 'IO TEE UNION SWITCH & SIGNAL GOMIPANY, OF SWISSVALE, PENNSYLVANIA, A COBZPORA'IIOIN' OF PENNSYLVANIA.

' ELEG'IRICAL Application filed April 1,

My invention relates 130 electrica l apparatus, and has for an object the provision of n0vel und improved means for alternatqly applying diflerences of otential of oppos1te polarities 130 a circuit in order to create an alternating current therein.

I will describe severa.l forms of apparat us embodying my invention, and will then pomt out the novel features thereof in claims.

In the accornpanying drawings, Fig. 1 15 a diagrammatic view showing one form of apparatus emb0dying my inve ntion. F1 gs. 2, 3 und 4 are diagrammatic V1eWs slgowmg modified forms of apparatus embodymg my invention.

Similar reference characters refer to sim1- lar parts in each of the views.

Referring first 120 Fig. 1, the reference characters R and R designate two rectjfiers having input circuits 1 and 1 respect1vely. The output circui t of rectifier R is connected across the terminals 0f an impedance A, and

the output circuit of rectifier R is connected cross the terminals of an impedance B. As hereshown, the impedances A and B are non-inductive resistance. The input circuits 1 and 1 are alternately supplied with eurrent, and the rectifiers are so connected that the diflerence of potential applied to the resistance A is opposite t0the diflerence of potential applied to resistan-ce B. The resistances A and B am connected in a circuit C which includes a reactor 3 and a condenser 4, and so it follows that alternating current is created in this circuit by the difl'erences 0f otential alternately applied t0 the resistances A and B. The circuit is preferably tuned by the reactor 3 and the condenser 4 to resonance at the frequency of the alternating current thus created in the circuit. A load of any suitable type may be connected across any appropriate part of the circuit,

APIPABA'IU'S 1931. Serial N0. 526,797.

H; Bowling, on June 23, 1930, Serial N0. 462,994.

It will be obvious that there am two mutually exclusive conditioris which make the app&ratus of Fig. 1 efficient. In order not to lose too much power in the resistance shunting. the rectifier wh'ose output is high, the values of the resistances A and B should be high; in order not to present t00 much series resistance in the tuned circuit C, however, the values of these resistances should be 10W. When the apparatus is so operated that the percentage change in the current through each resistance is large, the e1ficiency of the apparatus may be improved by using the resistance having relatively large temperature co-efficients of resistance Referring to Fig 2, the apparatus is the same as that shown in F ig. 1, except that re sistances A and B each having a relatively large positive temperature co-eflicient of rethat its resistance Will increase, with the resu1t that it will absorb less energy for the voltage impressed across it than if its resistance had remained constant. At the same time, the output from rectifier R is 10W, so thao lamp B is extinguished, with the resu1t that this lamp presents a relatively small series resistance to the curr ent in the tuned circuit C. The impedances 0f the lamps and of the other elements of the circuit should be so chosen that the hot lamp has a smaller impedance than the total impedance of the circuit plus that 0f the other lamp. The gain in the power efiiciency (power delivered t0 the tuned circuit divided by the total power sup plied to the lampsand tuned circuit), may

. with the apparatus shown in Fig. 2, be o i the mediu m of a movable contact member 7 which may alternately engage two fixed comtact members 7 und 7". The contact made up of th e elements 7, 7 and 7", may, for example, be the master re1ay w hich forms a part of the train-carried apparatus of what'is known as the code train control or cab signaling system. In this cas6, the load is preferably supplied from a winding 5 in inductive relation to the reactor 3, in order to prevent false indications due to a short circuit in the condenser 4.

Referring now to Fig. 4, the apparatus shown in this view is the same as that shown in Fig. 2, except that a railway track circuit is substituted for t'he tuned circuit C of the preceding view. In Fig. 4, the circuit including the lamps A and B is connected with the two track rails 9 and 9* of a railway track circuit, and this track circuit may, for example, be a portion of a code train control system, such as that referred t0 hereinbefore. When the output of rectifier R is high, the upper rail 9 will be positive, and the lower rail 9 will be negative. When the output 0f rectifier R is high, the lower rail 9 Will be positive, and the upper rail 9 will be negative.

Although I have herein shown and desciibed only a few form s of apparatus embodying my invention, it is understood that vafious changes and modifications may be made therein within the scope of the appended claims without departing from the spirit und scope of my invention.

Havingthus describ ed my invention, what I claim is l. In combination, a circuit including two resistances ea ch having a positive temperature co-eflicient of resistance, means for alternately applying difi'erences of potential of opposite polarities across said resistances to create an alternating current in said circuit,

and'means f01 tuning said circuit to resonance ab the frequency of such alternating current,

2. In combination, a circuit including two resistances each having a positive temperature co-eflicient of resistancd, and means f0r alternately applying diiferences of otential of opposite polarities across said resistances to create an alternating current in said circuit.

In testimony whereof I aflix my signature.

PHILIP H. DOWLING. 

